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WO2015023574A1 - Concentrateur solaire luminescent utilisant des composés organiques photostables chromophores - Google Patents

Concentrateur solaire luminescent utilisant des composés organiques photostables chromophores Download PDF

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Publication number
WO2015023574A1
WO2015023574A1 PCT/US2014/050504 US2014050504W WO2015023574A1 WO 2015023574 A1 WO2015023574 A1 WO 2015023574A1 US 2014050504 W US2014050504 W US 2014050504W WO 2015023574 A1 WO2015023574 A1 WO 2015023574A1
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Prior art keywords
optionally substituted
aryl
group
heteroaryl
solar concentrator
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Inventor
Weiping Lin
Hongxi Zhang
Mila RACHWAL
Peng Wang
Wan-Yun Hsieh
Kaoru Ueno
Michiharu Yamamoto
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Nitto Denko Corp
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Nitto Denko Corp
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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/40—Optical elements or arrangements
    • H10F77/42—Optical elements or arrangements directly associated or integrated with photovoltaic cells, e.g. light-reflecting means or light-concentrating means
    • H10F77/488—Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/06—Luminescent, e.g. electroluminescent, chemiluminescent materials containing organic luminescent materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/40—Optical elements or arrangements
    • H10F77/42—Optical elements or arrangements directly associated or integrated with photovoltaic cells, e.g. light-reflecting means or light-concentrating means
    • H10F77/45—Wavelength conversion means, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
    • C09K2211/10—Non-macromolecular compounds
    • C09K2211/1003—Carbocyclic compounds
    • C09K2211/1007—Non-condensed systems
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
    • C09K2211/10—Non-macromolecular compounds
    • C09K2211/1018—Heterocyclic compounds
    • C09K2211/1025—Heterocyclic compounds characterised by ligands
    • C09K2211/1059—Heterocyclic compounds characterised by ligands containing three nitrogen atoms as heteroatoms
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

Definitions

  • luminescent solar concentrator devices that utilize chromophore compounds to provide a wavelength conversion layer which is neutral in color and methods of using and of manufacturing these devices.
  • photovoltaic devices also known as solar cells
  • photovoltaic devices also known as solar cells
  • Several different types of mature photovoltaic devices have been developed, including a Silicon based device, a III-V and II- VI PN junction device, a Copper-Indium-Gallium-Selenium (CIGS) thin film device, an organic sensitizer device, an organic thin film device, and a Cadmium Sulfide/Cadmium Telluride (CdS/CdTe) thin film device, to name a few.
  • CIGS Copper-Indium-Gallium-Selenium
  • CdS/CdTe Cadmium Sulfide/Cadmium Telluride
  • concentrators require a mechanism to point the apparatus accurately at the sun, which involves the use of moving parts, a sensing system or other form of control. Furthermore, on cloudy days, when the majority of the light is diffuse and cannot be readily focused, this type of concentrator is of little use.
  • the neutral luminescent solar concentrator device comprises a wavelength conversion layer having a top surface, a bottom surface, and an edge surface substantially perpendicular to the top surface and the bottom surface, wherein the wavelength conversion layer comprises a photostable chromophore configured to convert a first portion of the absorbed photons to a different wavelength to provide converted photons, wherein the top surface is configured to receive photons from a photon source and to allow the photons to be absorbed by the wavelength conversion layer, wherein the edge surface is configured to expel a first portion of the converted photons out of the wavelength conversion layer, and wherein the bottom surface is configured to expel a second portion of converted photons out of the wavelength conversion layer as a transmitted light.
  • the wavelength conversion layer comprises a photostable chromophore configured to convert a first portion of the absorbed photons to a different wavelength to provide converted photons
  • the top surface is configured to receive photons from a photon source and to allow the photons to be absorbed by the
  • the chromophore is an organic compound.
  • the photostable chromophore exhibits less than about 30% degradation in maximum absorption peak intensity after 24 hours of continuous one sun (AM1.5G) irradiation at ambient temperature, wherein the transmitted light is neutral in color.
  • the photostable chromophore has a the UV wavelength region. In some embodiments, the photostable chromophore has outside of the wavelength range between about 400 nm to about 700 nm.
  • the neutral solar concentrator provides a flat absorption spectrum having a minimum max absorption that deviates from the maximum max absorption by less than or equal to 10% of the maximum absorption value in the wavelength region from about 400 nm to about 620 nm.
  • the neutral solar concentrator provides a flat absorption spectrum having a minimum absorption value that deviates from the maximum absorption by less than or equal to 10% of the maximum absorption value in the wavelength range between about 400 nm to about 700 nm.
  • the neutral solar concentrator provides a flat absorption spectrum having a minimum absorption value that deviates from the maximum absorption by less than or equal to 10% of the maximum absorption value in the wavelength range between about 400 nm to about 620 nm.
  • the neutral solar concentrator provides a flat absorption spectrum having a minimum absorption value that deviates from the maximum absorption by less than or equal to 10% of the maximum absorption value in the wavelength range between about 420 nm to about 620 nm.
  • the photostable chromophore is selected from perylene derivative dyes, benzotriazole derivative dyes, benzothiadiazole derivative dyes, benzo heterocyclic system derivative dyes, diazaborinine derivative dyes, or combinations thereof.
  • the neutral luminescent solar concentrator comprises at least one planar layer and at least one wavelength conversion layer, wherein the at least one planar layer and the at least one wavelength conversion layer may or may not be the same layer, and wherein the at least one planar layer comprises a major top surface for receipt of incident solar radiation, a bottom surface, and at least one edge surface through which radiation can escape.
  • a neutral colored wavelength conversion layer is achieved by using a chromophore (or chromophores) which absorb photons only in the UV wavelength range (e.g., from about 10 nm to about 400 nm).
  • a neutral colored wavelength conversion layer is achieved by using a mixture of chromophore compounds which absorb photons in the visible wavelength range, wherein the mixture of the chromophore compounds provides a film that has a flat absorption spectrum across the visible wavelength range.
  • the photons, once absorbed by the wavelength conversion layer are then re-emitted and are internally reflected and refracted within the neutral luminescent solar concentrator until they reach the edge surface.
  • the planar layer may also act to internally reflect and refract incident photons towards a solar energy conversion device.
  • a wavelength conversion layer comprising a UV absorbing chromophore provides a luminescent solar concentrator which is neutral in color.
  • the wavelength conversion layer is neutral in color and is transparent.
  • the at least one wavelength conversion layer comprises a polymer matrix and at least one organic photostable chromophore, wherein the chromophore has a maximum absorption peak at a wavelength less than 400nm, and wherein the neutral luminescent solar concentrator has a flat absorption of incident photons in the visible wavelength range such that the wavelength conversion layer is neutral in color, and the photons, once absorbed by the wavelength conversion layer, are then re-emitted and are internally reflected and refracted within the neutral luminescent solar concentrator until they reach the edge surface.
  • a mixture of multiple chromophore compounds provides a wavelength conversion layer which is neutral in color.
  • the wavelength conversion layer is neutral in color and is transparent.
  • the level of transparency of the wavelength conversion layer is dependent on the chromophore loading concentration.
  • the at least one wavelength conversion layer comprises a polymer matrix and two or more organic photostable chromophores, wherein the mixture of the two or more organic photostable chromophores provides a flat absorption of incident photons in the visible wavelength range such that the wavelength conversion layer is neutral in color, and the photons, once absorbed by the chromophores, are then re-emitted and are internally reflected and refracted within the neutral luminescent solar concentrator until they reach the edge surface.
  • the planar layer may also act to internally reflect and refract incident photons towards a solar energy conversion device.
  • the chromophores have individually have max values in the visible wavelength range.
  • some embodiments provide a highly efficient solar concentrator which utilizes multiple organic chromophores that absorb radiation in the visible light spectrum, while also allowing transmission of a portion of the radiation, so that the device may be used in place of window glass in buildings and cars.
  • Some embodiments of the invention provide a highly efficient solar concentrator which utilizes chromophores that absorb radiation only in the UV light spectrum, wherein the visible light transmission remains clear and the device may also be used in place of window glass in buildings and cars.
  • the transmission of the neutral color wavelength conversion film depends on the film thickness and the loading concentration of the chromophore compounds.
  • the neutral luminescent solar concentrator is photostable.
  • the use of organic photostable chromophore compounds, as disclosed herein, in the wavelength conversion layer of the neutral luminescent solar concentrator provides efficient solar harvesting along with good photostability, which consequently, improves the lifetime and efficiency of the solar energy conversion devices that are mounted to the neutral luminescent solar concentrator.
  • the neutral luminescent solar concentrator can be applied to one or multiple solar energy conversion devices.
  • a chromophore compound sometimes referred to as a luminescent dye or fluorescent dye, is a compound that absorbs photons of a particular wavelength or wavelength range, and re-emits the photon at a different wavelength or wavelength range.
  • Chromophores used in film media can greatly enhance the performance of solar cells and photovoltaic devices. However, such devices are often exposed to extreme environmental conditions for long periods of time, e.g., 20 plus years. As such, maintaining the stability of the chromophore over a long period of time is important.
  • An embodiment of the invention provides a neutral luminescent solar concentrator comprising at least one wavelength conversion layer, wherein said wavelength conversion layer comprises at least one chromophore and an optically transparent polymer matrix, and wherein the wavelength conversion layer receives as input at least one photon having a first wavelength, and provides as output at least one photon having a second wavelength which is different than the first.
  • the solar energy conversion module for the conversion of solar light energy into electricity.
  • the solar energy conversion module comprises at least one solar energy conversion device and a neutral luminescent solar concentrator.
  • the solar energy conversion device comprises a photovoltaic device or solar cell.
  • the solar energy conversion device is mounted to the edge surface of the neutral luminescent solar concentrator, such that the concentrated light in the neutral luminescent solar concentrator is directed into the solar energy conversion device for conversion into electricity.
  • incident light of a first wavelength is absorbed in the neutral luminescent solar concentrator by the chromophore compounds, where it is re-emitted at a second wavelength which is different than the first wavelength, and is then internally reflected and refracted within the neutral luminescent solar concentrator device until it reaches the solar energy conversion device where it is converted into electricity.
  • the solar energy conversion module comprising a solar energy conversion device and the neutral luminescent solar concentrator, as described herein, may include additional layers.
  • the solar energy conversion module may comprise an adhesive layer in between the solar cell and the neutral luminescent solar concentrator.
  • the solar energy conversion module may also comprise additional glass or polymer layers, which encapsulate the wavelength conversion layer(s), or may be placed on top of or underneath the wavelength conversion layers(s).
  • the glass or polymer layers may be designed to protect and prevent oxygen and moisture penetration into the wavelength conversion film.
  • the glass or polymer layers may be used as part of the neutral luminescent solar concentrator to internally refract and/or reflect photons that are emitted from the wavelength conversion layer(s) in a direction that is towards the solar energy conversion device.
  • the luminescent solar concentrator may further comprise additional polymer layers, or additional components within the polymer layers or wavelength conversion layer(s) such as sensitizers, plasticizers, UV absorbers and/or other components which may improve efficiency or stability.
  • the neutral luminescent solar concentrator may be applied to various solar energy conversion devices.
  • the solar energy conversion is a photovoltaic device or solar cell.
  • the neutral luminescent solar concentrator is applied to at least one solar cell or photovoltaic device selected from the group consisting of a silicon based device, a III-V or II-VI junction device, a Copper- Indium-Gallium-Selenium (CIGS) thin film device, an organic sensitizer device, an organic thin film device, or a Cadmium Sulfide/Cadmium Telluride (CdS/CdTe) thin film device.
  • the neutral luminescent solar concentrator is applied to multiple types of devices.
  • the neutral luminescent solar concentrator may be provided in various lengths and widths so as to accommodate different sizes and types of solar cells, and/or form entire solar panels.
  • Figures 1A-1B depict potential absorption spectra for individual chromophores in a film and a mixture of chromophores in a film.
  • Figures 2A and 2B illustrate the individual and mixture absorption spectrum of four chromophore compounds in a PVB film.
  • FIG. 3 illustrates an embodiment of a solar energy conversion module comprising a neutral luminescent solar concentrator with a wavelength conversion layer, wherein the wavelength conversion layer comprises one UV absorbing chromophore.
  • Figure 4 illustrates an embodiment of a solar energy conversion module comprising a neutral luminescent solar concentrator with a wavelength conversion layer, wherein the wavelength conversion layer comprises a mixture of two or more chromophores which absorb photons in the visible wavelength range.
  • Figure 5 illustrates an embodiment of a solar energy conversion module comprising a neutral luminescent solar concentrator a wavelength conversion layer and additional layers.
  • Figure 6 illustrates the absorption spectrum for a mixture of five chromophore compounds in a PVB film.
  • the present disclosure relates to luminescent solar concentrator devices that are neutral in color (e.g. colorless, about colorless, and/or as defined in more detail below). Also disclosed are solar energy conversion modules which utilize the neutral luminescent solar concentrators to enhance the photoelectric conversion efficiency of a solar energy capture and conversion.
  • the neutral luminescent solar concentrator comprises at least one photostable chromophore.
  • a solar energy conversion device is to be read broadly and includes any device that converts solar energy into electrical energy.
  • a "benzotriazole-type structure" includes the following
  • a "benzothiadiazole-type structure” includes the
  • a "diazaborinine-type structure” includes the following
  • alkyl refers to a branched or straight fully saturated acyclic aliphatic hydrocarbon group (i.e. composed of carbon and hydrogen containing no double or triple bonds). Alkyls include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, and the like.
  • heteroalkyl refers to an alkyl group comprising one or more heteroatoms. When two or more heteroatoms are present, they may be the same or different.
  • cycloalkyl used herein refers to saturated aliphatic ring system radical having three to twenty-five carbon atoms including, but not limited to, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like.
  • polycycloalkyl used herein refers to saturated aliphatic ring system radical having multiple cylcoalkyl ring systems.
  • alkenyl used herein refers to a monovalent straight or branched chain radical of from two to twenty-five carbon atoms containing at least one carbon double bond including, but not limited to, 1-propenyl, 2-propenyl, 2-methyl-l- propenyl, 1-butenyl, 2-butenyl, and the like.
  • alkynyl used herein refers to a monovalent straight or branched chain radical of from two to twenty-five carbon atoms containing a carbon triple bond including, but not limited to, 1-propynyl, 1-butynyl, 2-butynyl, and the like.
  • aryl used herein refers to homocyclic aromatic radical whether one ring or multiple fused rings. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, phenanthrenyl, naphthacenyl, fluorenyl, pyrenyl, and the like. Further examples include:
  • alkaryl or "alkylaryl” used herein refers to an alkyl- substituted aryl radical.
  • alkaryl include, but are not limited to, ethylphenyl, 9,9-dihexyl-9H-fluorene, and the like.
  • aralkyl or "arylalkyl” used herein refers to an aryl-substituted alkyl radical. Examples of aralkyl include, but are not limited to, phenylpropyl, phenylethyl, and the like.
  • heteroaryl refers to an aromatic group comprising one or more heteroatoms, whether one ring or multiple fused rings. When two or more heteroatoms are present, they may be the same or different. In fused ring systems, the one or more heteroatoms may be present in only one of the rings.
  • heteroaryl groups include, but are not limited to, benzothiazyl, benzoxazyl, quinazolinyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyridinyl, pyrrolyl, oxazolyl, indolyl, thiazyl and the like. Further examples of substituted and unsubstituted heteroaryl rings include:
  • alkoxy refers to straight or branched chain alkyl radical covalently bonded to the parent molecule through an — O— linkage.
  • alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, butoxy, n-butoxy, sec-butoxy, t-butoxy and the like.
  • heteroatom used herein refers to any atom that is not C (carbon) or H (hydrogen). Examples of heteroatoms include S (sulfur), N (nitrogen), and O (oxygen).
  • cyclic amino refers to either secondary or tertiary amines in a cyclic moiety.
  • examples of cyclic amino groups include, but are not limited to, aziridinyl, piperidinyl, N-methylpiperidinyl, and the like.
  • cyclic imido refers to an imide in the radical of which the two carbonyl carbons are connected by a carbon chain.
  • cyclic imide groups include, but are not limited to, 1,8-naphthalimide, pyrrolidine -2, 5-dione, lH-pyrrole- 2,5-dione, and the likes.
  • alcohol used herein refers to a radical -OH.
  • aryloxy used herein refers to an aryl radical covalently bonded to the parent molecule through an— O— linkage.
  • amino used herein refers to a radical -NR'R.
  • heteroamino refers to a radical -NR'R" wherein R' and/or R" comprises a heteroatom.
  • heterocyclic amino refers to either secondary or tertiary amines in a cyclic moiety wherein the group further comprises a heteroatom.
  • a substituted group is derived from the unsubstituted parent structure in which there has been an exchange of one or more hydrogen atoms for another atom or group.
  • the substituent group(s) is (are) one or more group(s) individually and independently selected from C 1 -C25 alkyl, C2-C25 alkenyl, C2-C25 alkynyl, C3-C25 cycloalkyl (optionally substituted with a moiety selected from the group consisting of halo, alkyl, alkoxy, alcohol, carboxyl, haloalkyl, CN, OH, -S0 2 -alkyl, -CF 3 , and -OCF 3 ), cycloalkyl geminally attached, C 1 -C25 heteroalkyl, C 3 -C25 heterocycloalkyl (e.g., tetrahydrofuryl) (optionally substituted with a moiety selected from the group consisting of halo, alkyl, alkoxy, alcohol, carboxyl, CN, -SCValkyl, -CF 3 , and -OCF 3 ), aryl (optionally substituted with
  • the terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result.
  • the terms “approximately,” “about,” and “substantially” are meant to encompass, for example, values that are within 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 7.5%, 10.0% relative to the value modified by those terms. For instance "about 30%,” where “about” represents 10% variability, is equivalent to a value of "30%) ⁇ 3%”).
  • the terms “approximately,” “about,” and “substantially” may represent variability that is more than 10.0% away from the value modified by those terms.
  • Luminescent dyes used in luminescent solar concentrators are typically down-shifting. These dyes convert shorter wavelengths of light to longer, useable, and/or more favorable wavelengths. The converted wavelengths can be internally reflected and refracted towards a photovoltaic device or solar cell, and converted into electricity.
  • Wavelength conversion films which utilize chromophore compounds are typically colored, depending on the chromophore.
  • a film with a chromophore which transmits photons in the blue light range (-400 - 500nm) will be a transparent blue color.
  • U.S. Patent No. 4661649 discloses a luminescent solar collector for high efficiency conversion of solar energy to electrical energy which utilizes specific commercially available organic dyes, GF Orange-Red, Fluorol 555, oxazine-4-perchlorate, LDS 730, LDS 750, BASF 241, BASF 339, and combinations thereof with each other or with GF Clear or with 3-phenyl-fluoranthene.
  • U.S. Patent Application Publication No. 2009/0151785 discloses a silicon based solar cell which contains a wavelength downshifting inorganic phosphor material.
  • U.S. Patent Application Publication No. 2011/0011455 discloses an integrated solar cell comprising a plasmonic layer, a wavelength conversion layer, and a photovoltaic layer.
  • U.S. Patent Application Publication No. 2010/0294339 discloses an integrated photovoltaic device containing a luminescent down-shifting material, however no example embodiments were constructed.
  • U.S. Patent Application Publication No. 2010/0012183 discloses a thin film solar cell with a wavelength down-shifting photo-luminescent medium; however, no examples are provided.
  • U.S. Patent Application Publication No. 2008/0236667 discloses an enhanced spectrum conversion film made in the form of a thin film polymer comprising an inorganic fluorescent powder.
  • AM1.5G is a standard terrestrial solar spectral irradiance distribution as defined by the American Society for Testing and Materials (ASTM) standard 2006, see ASTM G- 173-03.
  • Some solar concentrators comprise homogeneous mediums containing a fluorescent species.
  • the fluorescent species typically has an emission wavelength range with minimal overlap of the absorption range so that re-absorption of the emitted wavelength is avoided.
  • the solar concentrator can be configured to trap emitted photons by total internal reflection, urging them towards the edge of the collector, which is usually a thin rectangular plate. The concentration of light trapped in the plate is proportional to the ratio of the surface area to the edge surface.
  • Luminescent solar concentrators may be able to absorb solar light from a large area and concentrate the emitted fluorescent light to a small area. This small area can then transmit the light to, for example, solar cells.
  • Potential advantages of luminescent solar concentrators over conventional solar concentrators include: high collection efficiency of both direct and diffuse light, good heat dissipation from the large area of the collector plate in contact with air, so that essentially "cold light" is used for converter devices such as silicon cells, whose efficiency is reduced by high temperatures. Also, with luminescent solar concentrators tracking of the sun is unnecessary, and choice of the luminescent species allows optimal spectral matching of the concentrated light to the maximum sensitivity of the photovoltaic (PV) process, minimizing undesirable side reactions in the solar cells.
  • PV photovoltaic
  • the luminescent solar concentrator comprises a wavelength conversion layer, a plurality of conversion layers, or a conversion device that is neutral in color.
  • the wavelength conversion device comprises a plurality of wavelength conversion devices which, by themselves, may individually be colored, but, when combined in a conversion device are neutral. These neutral conversion layers and/or devices allow highly efficient solar harvesting with substantially undistorted color, making these conversion layers and devices suitable for applications such as windows (e.g., in vehicles, buildings, etc.) or for other applications requiring visibility through a surface.
  • a neutral conversion layer or device is provided by using a one or more chromophores together that absorb (and/or transmit) in the visible light range that, together, result in a flat absorption or emission spectrum in the visible light range (i.e., a neutral conversion layer, a plurality of conversion layers, or a conversion device).
  • one or more chromophores that do not substantially absorb and/or transmit in the visible light range are used to provide a neutral colored conversion layer or conversion device (e.g. UV absorbing chromophores, i.e., having a max in the UV region).
  • the one or more chromophores provide a neutral color by yielding a "flat" absorption spectrum in a region of the visible wavelength range from about 400 nm to about 700 nm, from about 360 nm to about 700 nm, or from about 400 nm to about 620 nm.
  • a flat absorption of photons provides a flat absorption spectrum and a film having a flat absorption spectrum with a neutral color.
  • a flat absorption i.e., neutral color
  • a minimum max absorption of 0.90 or higher compared to a maximum m ax absorption value of 1.0 a minimum max absorption of 0.90 or higher compared to a maximum m ax absorption value of 1.0.
  • a flat absorption results (i.e., neutral absorption) where the minimum max absorption value deviates from the maximum max absorption by less than or equal to about 30%>, about 20%>, about 10%>, about 7.5%, about 5%, about 3.0%), about 2.0%, about 1.0%, or about 0.5%> of the maximum max absorption value in one of the above regions of the visible wavelength range. Examples showing a minimum absorption and maximum max absorption are as shown in Figure 1 A).
  • a flat absorption can be obtained when the minimum absorption value deviates from the maximum absorption by less than or equal to 10% of the maximum absorption value in one of the above regions of the visible wavelength range (where minimum absorption and maximum absorption are as depicted in Figure IB). In some embodiments, a flat absorption results where the minimum absorption value deviates from the maximum absorption by less than or equal to about 30%, about 20%, about 10%, about 7.5%, about 5%, about 3.0%, about 2.0%, about 1.0%, or about 0.5% of the maximum absorption value in one of the above regions of the visible wavelength range.
  • Figures 2 A and 2B as described in more detail in the EXAMPLES section, show actual spectra of chromophores with flat absorption spectra that yield a neutral color wavelength conversion device.
  • a flat emission is obtained wherein the minimum emission value is within equal to or less than about 5% of the maximum emission value within one of the above regions of the visible wavelength range.
  • a flat emission spectrum results where the minimum emission value is within equal to or less than about 30%, about 20%, about 10%>, about 5%, about 2.0%, or about 0.5%> of the maximum emission value within the visible wavelength range.
  • a flat emission results where the minimum emission value is within equal to or less than about 30%), about 20%o, about 10%>, about 5%, about 2.0%>, or about 0.5%> of the maximum emission value within the visible wavelength range.
  • the neutral wavelength conversion film or device is provided using one or more chromophores that do not absorb substantially in the visible light range.
  • the one or more chromophores absorb only photons in the UV wavelength range so that the wavelength conversion layer absorbs only UV wavelengths for highly efficient solar harvesting.
  • the one or more chromophores that absorb light in in the UV wavelength range and not light in the visible wavelength range provide a neutral wavelength conversion film or device.
  • the neutral color is achieved using one or more chromophores that absorb in, or together have a flat absorption in the wavelength range from about 360 nm to about 700 nm, about 400 nm to about 700 nm, about 400 nm to about 620 nm, or about 420 nm to about 620 nm to yield a neutral wavelength conversion layer or device.
  • the neutral color is achieved using one or more chromophores that absorb in, or together have a flat absorption in the wavelength range from about 300 nm to about 400 nm, about 400 nm to about 500 nm, about 500 nm to about 600 nm, or about 600 nm to about 700 nm to yield a neutral wavelength conversion layer or device.
  • flat absorption means that all photons in the visible light range are absorbed similarly when passing into the film, so that the film does not assume any color tinting.
  • the transparency of the film is determined by the film thickness and/or the chromophore loading concentration.
  • the neutral film also provides efficient conversion of solar radiation. The use of a neutral color film as the wavelength conversion layer allows the neutral luminescent solar concentrator to be used in place of window glass (e.g. in buildings, cars, etc.), creating a much larger surface area on these structures for solar harvesting, while also maintaining the neutral transparency for clear visibility.
  • the neutral luminescent solar concentrator device comprises a wavelength conversion layer having a top surface, a bottom surface, and an edge surface substantially perpendicular to the top surface and the bottom surface, wherein the wavelength conversion layer comprises a photostable chromophore configured to convert a first portion of the absorbed photons to a different wavelength to provide converted photons, wherein the top surface is configured to receive photons from a photon source and to allow the photons to be absorbed by the wavelength conversion layer, wherein the edge surface is configured to expel a first portion of the converted photons out of the wavelength conversion layer, and wherein the bottom surface is configured to expel a second portion of converted photons out of the wavelength conversion layer as a transmitted light.
  • the wavelength conversion layer comprises a photostable chromophore configured to convert a first portion of the absorbed photons to a different wavelength to provide converted photons
  • the top surface is configured to receive photons from a photon source and to allow the photons to be absorbed by the
  • the neutral luminescent solar concentrator device comprises at least one planar layer and at least one wavelength conversion layer.
  • the planar layer can be the wavelength conversion layer.
  • the wavelength conversion layer comprises a polymer matrix and one or more organic photostable luminescent chromophore.
  • the neutral luminescent solar concentrator may be positioned adjacent to at least one solar energy conversion device or solar cell device and the neutral luminescent concentrator acts to absorb incident photons of the particular wavelength range, and re-emit those photons at a different wavelength, wherein the re-emitted photons are internally reflected and refracted until they reach the solar energy conversion device or solar cell where they can be absorbed and converted into electricity.
  • the neutral luminescent solar concentrator at least one of the chromophores is a down-shifting dye, meaning a chromophore that converts photons of high energy (short wavelengths) into lower energy (long wavelengths).
  • at least one of the chromophores is an up-shifting dye, meaning a chromophore that converts photons of lower energy (longer wavelengths) into higher energy (shorter wavelengths).
  • the wavelength conversion film comprises both an up-conversion chromophore and a downshifting chromophore.
  • the at least one chromophore is an organic dye.
  • the at least one chromophore is an inorganic dye. In some embodiments, the at least one chromophore is selected from perylene derivative dyes, benzotriazole derivative dyes, diazaborinine derivative, or benzothiadiazole derivative dyes. In some embodiments, the down-shifting chromophore may independently be a derivative of perylene, benzotriazole, benzothiadiazole, benzo heterocyclic systems, and/or combinations thereof, as are described in U.S. Provisional Patent Application Nos. 61/430,053, 61/485,093, 61/539,392, 61/749,225, and U.S. Pat. Applications Nos. 13/626,679 and 13/978,370, which are hereby incorporated by reference in their entireties.
  • the above mentioned organic chromophores are especially suitable for use in the solar energy harvesting applications because they are surprisingly more stable in harsh environmental conditions than currently available wavelength converting chromophores. This stability (together with their ability to provide a flat color profile) makes these chromophores advantageous in their use as wavelength conversion materials for solar cell applications. Without such photostability, these chromophores would degrade and lose efficiency, limiting their utility.
  • the photostability of chromophores can be measured by fabricating a wavelength conversion film containing the chromophore compound and then measuring the absorption peak prior to exposure and after exposure to continuous one sun (AM1.5G) irradiation at ambient temperature.
  • A1.5G continuous one sun
  • the preparation of such a wavelength conversion film is described in the EXAMPLES section below.
  • the amount of remaining chromophore after irradiation can be measured using the maximum absorption of the chromophore before and after irradiation using the following equation:
  • the % degradation can be measured using the following equation: (Absorption Peak Intensity Before Irradiation - Absorption Peak Intensity After Irradiation)
  • a photostable chromophore shows less than about 30%, 20%, 15%), 10%o, 5%), 2.5%), 1.0%, or 0.5%> degradation in maximum absorption peak intensity after 24 hours of continuous one sun (AM1.5G) irradiation at ambient temperature.
  • a photostable chromophore has greater than about 70%>, 80%>, 85%, 90%o, 95%o, 97.5%o, 99.0%), or 99.5% of the chromophore remaining (as measured by maximum absorption peak intensity) after 24 hours of continuous one sun (AM1.5G) irradiation at ambient temperature.
  • a UV absorbing chromophore in the wavelength conversion layer may be used to create a neutral color wavelength conversion film which does not absorb substantially within the visible light spectrum.
  • a neutral color wavelength conversion layer may be achieved by using only UV absorbing chromophores.
  • the wavelength conversion layer does not substantially absorb in the visible wavelength range, leaving the film neutral and clearly transparent.
  • the transparency of the film is determined by the film thickness, the type of polymer or glass material used, and/or the chromophore loading concentration.
  • the neutral film also provides efficient conversion of solar radiation.
  • the use of a neutral color film as the wavelength conversion layer allows the neutral luminescent solar concentrator to be used as windows (e.g. in buildings, cars, etc.) and in other applications where clear material is useful, creating a much larger surface area on these structures for solar harvesting, while also maintaining the neutral transparency for clear visibility.
  • the neutral luminescent solar concentrator comprises a top surface, wherein the top surface is configured to receive incident photons, and further comprises at least one wavelength conversion layer, wherein the wavelength conversion layer comprises at least one chromophore having a maximum absorption wavelength of less than about 400nm, wherein a portion of the incident UV photons are absorbed into the wavelength conversion layer.
  • at least one edge surface is configured to allow a first portion of the absorbed photons to escape through the edge surface, and a bottom surface, wherein at least a second portion of the absorbed photons escape through the bottom surface.
  • the neutral luminescent solar concentrator does not absorb photons within the wavelength range of about 400 nm to about 620 nm. In some embodiments, the neutral luminescent solar concentrator has a flat absorption spectrum across the visible wavelength range because the wavelength conversion layer does not absorb visible wavelengths.
  • the at least one UV absorbing chromophore comprises a structure as given by the following general formula (I):
  • Ri and R 2 in formula (I) is selected from the group consisting of Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, arylalkyl; and R 3 may be optionally substituted with one or more of any of the following substituents: Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, aryl, heteroaryl, OH, C m H 2m+ iO ether, C m H 2m+ iCO ketone, C m H 2m+ iC0 2 carboxylic ester, C m H 2m+ iOCO carboxylic ester, ArO aryloxy, ArCO aryl ketone, ArC0 2 ester of aryl- carboxylic acid,
  • the at least one UV absorbing chromophore com rises a structure as given by the following general formulae (Il-a) and (Il-b):
  • R in formula Il-a and formula Il-b is selected from the group consisting of Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, arylalkyl; and R may be optionally substituted with one or more of any of the following substituents: Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, aryl, heteroaryl, OH, C m H 2m+ iO ether, C m H 2m+ iCO ketone, C m H 2 m + iC0 2 carboxylic ester, C m H 2m+ iOCO carboxylic ester, ArO aryloxy, ArCO aryl ketone, ArC0 2 ester of aryl-carboxy
  • R 4 , R 5 , and R 6 in formula Il-a and formula II -b are independently selected from the group consisting of Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, aryl, heteroaryl, arylalkyl, heteroarylalkyl, C0 2 C m H 2m+ i carboxylic ester, (C m H 2m+ i)(C p H 2p+ i)NCO amide, c-(CH 2 ) s NCO amide, COC m H 2m+ i ketone, COAr, S0 2 C m H 2m+ i sulfone, S0 2 Ar sulfone, (C m H 2m+ i)(C p H 2p+ i)S0 2 sulfonamide, c-(CH 2 ) s S0
  • L in formula Il-b is selected from the group consisting of Ci_ 25 alkyl, Ci_ 2 5 heteroalkyl, C 2 _ 25 alkenyl; and L may be optionally substituted with one or more of any of the following substituents: Ci_ 25 alkyl, Ci_ 25 heteroalkyl, C 2 _ 25 alkenyl, C 3 _ 25 cycloalkyl, polycycloalkyl, heterocycloalkyl, aryl, heteroaryl, OH, C m H 2m+ iO ether, C m H 2m+ iCO ketone, C m H 2m+ iC0 2 carboxylic ester, C m H 2m+ iOCO carboxylic ester, ArO aryloxy, ArCO aryl ketone, ArC0 2 ester of aryl-carboxylic acid, ArOCO carboxylic ester of phenol, (C m H 2m+ i)(C p H 2p+ i)N
  • wavelength conversion films which absorb photons in the visible light spectrum are colored.
  • a wavelength conversion film comprising a chromophore which absorbs photons in the 400 nm to 500 nm range may be blue in color
  • a film with a chromophore which absorbs photons in the 500 nm to 620 nm range may be orange or red in color. Due to their coloration of the film they have limited utility as viewing windows.
  • the inventors have surprisingly discovered that certain mixtures of multiple chromophore compounds provide a wavelength conversion film which is neutral in color, with adequate transmission, and highly efficient solar harvesting. This neutral color film is very useful for replacement of window glass in buildings and cars.
  • a wavelength conversion film having neutral color i.e. a neutral wavelength conversion film
  • the absorption may vary depending on the medium that the chromophores are dispersed into (e.g., PVB versus EVA). Therefore, in some embodiments, a different mixture of chromophore compounds may be required for a depending on the polymer matrix.
  • chromophores there is no limit to the number of chromophores that can be mixed into the wavelength conversion layer keeping in mind the goal is to produce a neutral wavelength conversion film, neutral conversion films, and/or devices.
  • the chromophores are individually selected by their absorption properties so that the mixture provides absorption across the entire visible spectrum.
  • Absorption wavelength range and absorption intensity are specific to each individual chromophore.
  • the concentration of each chromophore in the film can be adjusted to provide a flat absorption depending on the chromophore and/or chromophores.
  • the wavelength conversion layer comprises a mixture of one or more chromophores. In some embodiments, the wavelength conversion layer comprises a mixture of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more chromophores.
  • one or more chromophore in the neutral luminescent solar concentrator comprises a structure as given by the general formula (I), shown above. In some embodiments, one or more chromophore in the neutral luminescent solar concentrator comprises a structure as given by the general formulae (Il-a) and (Il-b), shown above.
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formula (Ill-a) or (Ill-b):
  • the other electron donor groups may be occupied by another electron donor, a hydrogen atom, or another neutral substituent.
  • at least one of the D 1 , D 2 , and L' is a group which increases the electron density of the 2H- benzo[ ⁇ i][l,2,3]triazole system to which it is attached.
  • i is an integer in the range of 0 to 100. In some embodiments, i is an integer in the range of 0 to 50, 0 to 30, 0 to 10, 0 to 5, or 0 to 3. In some embodiments, i is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
  • a 0 and A 1 are each independently selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, and optionally substituted carboxy, and optionally substituted carbonyl.
  • a 0 and A 1 are each optionally substituted heteroaryl or optionally substituted cyclic imido; wherein the substituent for optionally substituted heteroaryl and optionally substituted cyclic imido is selected from the group consisting of alkyl, aryl and halogen.
  • At least one of the A 0 and A' is selected from the group consisting of: optionally substituted pyridinyl, optionally substituted pyridazinyl, optionally substituted pyrimidinyl, optionally substituted pyrazinyl, optionally substituted triazinyl, optionally substituted quinolinyl, optionally substituted isoquinolinyl, optionally substituted quinazolinyl, optionally substituted phthalazinyl, optionally substituted quinoxalinyl, optionally substituted naphthyridinyl, and optionally substituted purinyl.
  • a 0 and A 1 are each optionally substituted alkyl. In other embodiments, A 0 and A 1 are each optionally substituted alkenyl. In some embodiments, at least one of the A 0 and A 1 is selected from the rou consistin of: optionally substituted alkyl.
  • a 2 is selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted o o
  • R 7 is selected from the group consisting of H, alkyl, alkenyl, aryl, heteroaryl, aralkyl, alkaryl; and R 8 is selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted arylene, optionally substituted heteroarylene, ketone, and ester; or R 7 and R 8 may be connected together to form a ring.
  • a 2 is selected from the group consisting of optionally substituted arylene, optionally substituted heteroarylene, and , wherein Ar, R 7 and R 8 are as described above.
  • D 1 and D 2 are each independently selected from the group consisting of hydrogen, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, amido, cyclic amido, and cyclic imido, provided that D 1 and D 2 are not both hydrogen.
  • D 1 and D 2 are each independently selected from the group consisting of hydrogen, optionally substituted aryl, optionally substituted heteroaryl, and amino, provided that D 1 and D 2 are not both hydrogen. In some embodiments, D 1 and D 2 are each independently selected from the group consisting of hydrogen, optionally substituted aryl, optionally substituted heteroaryl, and diphenylamino, provided that D 1 and D 2 are not both hydrogen.
  • D 1 and D 2 are each independently optionally substituted aryl. In some embodiments, D 1 and D 2 are each independently phenyl optionally substituted by alkoxy or amino. In other embodiments, D 1 and D 2 are each independently selected from hydrogen, optionally substituted benzofuranyl, optionally substituted thiophenyl, optionally substituted furanyl, dihydrothienodioxmyl, optionally substituted benzothiophenyl, and optionally substituted dibenzothiophenyl, provided that D 1 and D 2 are not both hydrogen.
  • the substituent for optionally substituted aryl and optionally substituted heteroaryl may be selected from the group consisting of alkoxy, aryloxy, aryl, heteroaryl, and amino.
  • L 1 is independently selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted alkynylene, optionally substituted arylene, optionally substituted heteroarylene. In some embodiments, L 1 is selected from the group consisting of optionally substituted heteroarylene and optionally substituted arylene.
  • At least one of the L 1 is selected from the group consisting of: 1 ,2-ethylene, acetylene, 1 ,4-phenylene, l,l '-biphenyl-4,4'-diyl, naphthalene-
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formula (IV-a) or (IV-b):
  • i is an integer in the range of 0 to 100. In some embodiments, i is an integer in the range of 0 to 50, 0 to 30, 0 to 10, 0 to 5, or 0 to 3. In some embodiments, i is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
  • Ar is optionally substituted aryl or optionally substituted heteroaryl.
  • aryl substituted with an amido or a cyclic imido group at the N-2 position of the 2H-benzo[ ⁇ i][l,2,3]triazole ring system provides unexpected and improved benefits.
  • R 9 is or optionally substituted cyclic imido
  • R 7 is each indepedently selected from the group consisting of ⁇ , alkyl, alkenyl, aryl, heteroaryl, aralkyl, alkaryl
  • R 10 is each independently selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted aryl, optionally substituted heteroaryl; or R 7 and R 10 may be connected together to form a ring.
  • R 9 is optionally substituted cyclic imido selected from the group consisting of:
  • R 8 is selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted arylene, optionally substituted heteroarylene.
  • D 1 and D 2 are each independently selected from the group consisting of hydrogen, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, amido, cyclic amido, and cyclic imido, provided that D 1 and D 2 are not both hydrogen.
  • L 1 is independently selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted alkynylene, optionally substituted arylene, optionally substituted heteroarylene.
  • At least one of the L 1 is selected from the group consisting of: 1 ,2-ethylene, acetylene, 1 ,4-phenylene, l,l '-biphenyl-4,4'-diyl, naphthalene-
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formula (V-a) or (V-b):
  • i is an integer in the range of 0 to 100. In some embodiments, i is an integer in the range of 0 to 50, 0 to 30, 0 to 10, 0 to 5, or 0 to 3. In some embodiments, i is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
  • a 0 and A 1 are each independently selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted amido, optionally substituted alkoxy, optionally substituted cabonyl, and optionally substituted carboxy.
  • a 0 and A 1 are each independently unsubstituted alkyl or alkyl substituted by a moiety selected from the group consisting of: -NR ", -OR, - COOR, -COR, -CONHR, -CONRR", halo and -CN; wherein R is Ci-C 20 alkyl, and R" is hydrogen or Ci-C 2 o alkyl.
  • the optionally substituted alkyl may be optionally substituted C 1 -C40 alkyl.
  • a 0 and the A 1 are each independently C 1 -C40 alkyl or Ci-C 2 o haloalkyl.
  • a 0 and A 1 are each independently Ci-C 20 haloalkyl, C 1 -C40 arylalkyl, or Ci-C 2 o alkenyl.
  • each R 11 is independently selected from the group consisting of optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, and amino.
  • each R 11 is independently selected from the group consisting of optionally substituted Ci-C 20 alkoxy, optionally substituted Ci- C 2 o aryloxy, optionally substituted Ci-C 2 o acyloxy, and Ci-C 2 o amino.
  • R 11 may attach to phenyl ring at ortho and/or para position.
  • R 11 may be aryloxy represented by the following formulae: ArO or O- CR-OAr where R is alkyl, substituted alkyl, aryl, or heteroaryl, and Ar is any substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl.
  • a 2 is selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted
  • R is selected from the group consisting of H, alkyl, alkenyl, aryl, heteroaryl, aralkyl, and alkaryl; and R 8 is selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted arylene, optionally substituted heteroarylene, ketone, and ester; or R 7 and R 8 may be connected together to form a ring.
  • R 7 is selected from the group consisting of H, Ci-C 2 o alkyl, Ci-C 20 alkenyl, Ci-C 2 o aryl, Ci-C 2 o heteroaryl, Ci-C 2 o aralkyl, and Ci-C 2 o alkaryl; and R 8 is selected from the group consisting of optionally substituted Ci-C 2 o alkylene, optionally substituted Ci-C 2 o alkenylene, optionally substituted Ci-C 2 o arylene, optionally substituted Ci-C 2 o heteroarylene, ketone, and ester
  • L 1 is independently selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted alkynylene, optionally substituted arylene, optionally substituted heteroarylene.
  • At least one of the L 1 is selected from the group consisting of: 1 ,2-ethylene, acetylene, 1 ,4-phenylene, l , l '-biphenyl-4,4'-diyl, naphthalene-
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formulae (VI):
  • i is an integer in the range of 0 to 100. In some embodiments, i is an integer in the range of 0 to 50, 0 to 30, 0 to 10, 0 to 5, or 0 to 3. In some embodiments, i is 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10. [0136]
  • D 1 and D 2 are independently selected from the group consisting of optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, amido, cyclic amido, and cyclic imido; j is 0, 1 or 2, and k is 0, 1, or 2.
  • Y 1 and Y 2 are independently selected from the group consisting of optionally substituted aryl, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkoxy, and optionally substituted amino; and
  • L 1 is independently selected from the group consisting of optionally substituted alkylene, optionally substituted alkenylene, optionally substituted alkynylene, optionally substituted arylene, optionally substituted heteroarylene.
  • At least one of the L 1 is selected from the group consisting of: 1 ,2-ethylene, acetylene, 1 ,4-phenylene, l,l '-biphenyl-4,4'-diyl, naphthalene-
  • the electron linker represents a conjugated electron system, which may be neutral or serve as an electron donor itself. In some embodiments, some examples are provided below, which may or may not contain additional attached substituents.
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formula (Vll-a) or (Vll-b):
  • R and R in formula (Vll-a) are each independently selected from the group consisting of hydrogen, Ci-Cio alkyl, C3-C 10 cycloalkyl, C 1 -C 10 alkoxy, C 6 -Ci 8 aryl, and C 6 - C 20 aralkyl; m and n in formula (Vll-a) are each independently in the range of from 1 to 5; and R 15 and R 16 in formula (Vll-b) are each independently selected from the group consisting of a C 6 -Ci 8 aryl and C 6 -C 20 aralkyl.
  • the other cyano group is not present on the 10-position of the perylene ring. In some embodiments, if one of the cyano groups on formula (VII -b) is present on the 10-position of the perylene ring, then the other cyano group is not present on the 4-position of the perylene ring.
  • R 13 and R 14 are independently selected from the group consisting of hydrogen, Ci-C 6 alkyl, C 2 -C 6 alkoxyalkyl, and C 6 -Ci 8 aryl. In some embodiments, R 13 and R 14 are each independently selected from the group consisting of isopropyl, isobutyl, isohexyl, isooctyl, 2-ethyl-hexyl, diphenylmethyl, trityl, and diphenyl. In some embodiments, R 15 and R 16 are independently selected from the group consisting of diphenylmethyl, trityl, and diphenyl. In some embodiments, each m and n in formula (VII- a) is independently in the range of from 1 to 4.
  • the perylene diester derivative represented by the general formula (VII- a) or general formula (Vll-b) can be made by known methods, such as those described in International Publication No. WO 2012/094409, the contents of which are hereby incorporated by reference in their entirety.
  • one or more chromophore in the neutral luminescent solar concentrator is represented by formula (VIII):
  • Het is selected from the group consisting of:
  • X is selected from the group consisting of -N(A 0 )-, -0-, -S-, -Se-, and -Te-
  • Z is selected from the group consisting of -N(Ra)-, -0-, -S-, -Se-, and -Te-.
  • Each Ao in formula VIII is selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted acyl, optionally substituted carboxy, and optionally substituted carbonyl.
  • R a , R b , and R c , of formula VIII are independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or R a and R b , or R b and R c , or R a and R c , together form an optionally substituted al
  • each R a , R b , and R c , of formula VIII are independently selected from the group consisting of hydrogen, optionally substituted Ci_g alkyl, optionally substituted C 6-1 o aryl, and optionally substituted C 6 -io heteroaryl.
  • each R a , R b , and R c , of formula VIII are independently selected from the group consisting of hydrogen, Ci_ 8 alkyl, C 6 _io aryl, and C 6 _io heteroaryl, wherein Ci_ 8 alkyl, C 6 -io aryl, and C 6 -io heteroaryl may each be optionally substituted by optionally substituted C3-10 cycloalkyl, optionally substituted Ci_g alkoxy, halo, cyano, carboxyl, optionally
  • R a and R b , or R b and R c , or R a and R c together form an optionally
  • Di and D 2 are independently selected from the group consisting of hydrogen, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, amido, cyclic amido, and cyclic imido, -aryl-NR'R", -aryl-aryl-NR'R", and -heteroaryl-heteroaryl-R'; wherein R' and R" are independently selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted aryl; provided that Di and D 2 are not both hydrogen, and Di and D 2 are not optionally substituted thiophene or optionally substituted furan.
  • each Di and D 2 of formula VIII are independently C 6 -io aryl or optionally substituted C 6 -io aryl.
  • L of formula VIII is independently selected from the group consisting of optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, amino, amido, imido, optionally substituted alkoxy, acyl, carboxy, provided that L is not optionally substituted thiophene or optionally substituted furan.
  • the chromophore is represented by formula VIII, wherein L is independently selected from the group consisting of haloalkyl, alkylaryl, alkyl substituted heteroaryl, arylalkyl, heteroamino, heterocyclic amino, cycloamido, cycloimido, aryloxy, acyloxy, alkylacyl, arylacyl, alkylcarboxy, arylcarboxy, optionally substituted phenyl, and optionally substituted naphthyl.
  • L is independently selected from the group consisting of haloalkyl, alkylaryl, alkyl substituted heteroaryl, arylalkyl, heteroamino, heterocyclic amino, cycloamido, cycloimido, aryloxy, acyloxy, alkylacyl, arylacyl, alkylcarboxy, arylcarboxy, optionally substituted phenyl, and optionally substituted naphthyl.
  • the chromophore is represented by formula VIII, provided that when Het is:
  • R a and R b are not both hydrogen, and Di and D 2 are independently selected
  • the chromophore is represented by formula VIII,
  • R a and Rb are not both hydrogen.
  • the chromophore is represented by formula VIII,
  • Het is from the group consisting of -N(A 0 )- and -Se-
  • Z is selected from the group consisting of -N(R a )- and -S-
  • Di and D 2 are independently
  • the chromophore is represented by formula
  • the chromophore is represented by formula VIII,
  • Di and D 2 do not comprise bromine.
  • i is 0 or an integer in the range of 1 to 100. In some embodiments, i is 0 or an integer in the range of 1 to 50, 1 to 30, 1 to 10, 1 to 5, or 1 to 3. In some embodiments, i is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. [0160] In some embodiments, one or more chromophore in the neutral luminescent solar concentrator is represented by formula (IX-a) or (IX-b):
  • Het 2 is selected from the group consisting of:
  • Z is selected from the group consisting of -N(R a )-, -0-,
  • R a , R b , and R c , in formula IX-a and formula IX-b is independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or R a and Rb, or Rb and R c , or R a and R
  • each R a , R b , and R c is independently selected from the group consisting of hydrogen, optionally substituted Ci_g alkyl, optionally substituted C 6- 10 aryl, and optionally substituted C 6-1 o heteroaryl.
  • each R a , Rb, and Rc, of formula (IX-a) and formula (IX-b) are independently selected from the group consisting of hydrogen, Ci_ 8 alkyl, C 6 _io aryl, and C 6 _io heteroaryl, wherein Ci_ 8 alkyl, C 6 _io aryl, and C 6 -io heteroaryl may each be optionally substituted by optionally substituted C3-10 cycloalkyl, optionally substituted Ci_g alkoxy, halo boxyl, optionally substituted
  • C 6 _io aryl optionally substituted C 6 _io aryloxy, , or
  • R a and Rb, or R b and R c , or R a and R c together form an optionally substituted
  • g system selected from the group consisting of:
  • Each of the Rj and R e in formula IX-a and formula IX-b is independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or Rd and Rs together form an optionally substituted ring or an optionally substituted polycyclic ring system, wherein each ring is
  • Each of D l s D 2 , D 3 , and D 4 in formula IX-a and formula IX-b are each independently C 6 -io aryl or optionally substituted C 6 -io aryl.
  • each of D l s D 2 , D 3 , and D 4 in formula IX-a and formula IX-b are each independently C 6 -io aryl or optionally substituted C 6 -io aryl.
  • the chromophore is represented by formula IX-a
  • the chromophore is represented by formula IX-a
  • the chromophore is represented by formula IX-a
  • the chromophore is represented by formula IX-a
  • At least one of the chromophores in the neutral luminescent solar concentrator is represented by formula (X-a) or (X-b):
  • Het 3 is selected from the group consisting of
  • X is selected from the group consisting of -N(A 0 )-, -0-, -S-, -Se-, and -Te-.
  • Each Ao of formula X-a and formula X-b is selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted acyl, optionally substituted carboxy, and optionally substituted carbonyl.
  • a 0 is Ci_ 8 alkyl.
  • Each R a , Rb, and R c , of formula X-a and formula X-b is independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or Ra and Rb, or Rb and Rc, or R a and R c , together form an optionally substituted
  • each R a , Rb, and R c is independently selected from the group consisting of hydrogen, optionally substituted Ci_g alkyl, optionally substituted C 6- io aryl, and optionally substituted C 6-1 o heteroaryl.
  • each R a , Rb, and Rc, of formula X-a and formula X-b are independently selected from the group consisting of hydrogen, Ci_ 8 alkyl, C 6 _io aryl, and C 6 _io heteroaryl, wherein Ci_ 8 alkyl, C 6 _io aryl, and C 6 _io heteroaryl may each be optionally substituted by optionally substituted C3-10 cycloalkyl, optionally substituted Ci_g alkoxy, halo, cyano, carboxyl, optionally substituted C 6 -io aryl,
  • Each Rd and R e of formula X-a and formula X-b is independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkoxyalkyl, optionally substituted alkenyl, optionally substituted heteroalkyl, optionally substituted heteroalkenyl, optionally substituted aryl, optionally substituted arylalkyl, optionally substituted heteroaryl, optionally substituted cylcoalkyl, optionally substituted cycloalkenyl, optionally substituted cycloheteroalkyl, optionally substituted cycloheteroalkenyl, optionally substituted amino, optionally substituted amido, optionally substituted cyclic amido, optionally substituted cyclic imido, optionally substituted alkoxy, optionally substituted carboxy, and optionally substituted carbonyl; or Rd and Rs together form an optionally substituted ring or an optionally substituted polycyclic ring system, wherein each ring is independently
  • Each D l s D 2 , D 3 , and D 4 of formula X-a and formula X-b is independently selected from the group consisting of hydrogen, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted acyloxy, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted amino, amido, cyclic amido, and cyclic imido, -aryl-NR'R", -aryl-aryl-NR'R", and - heteroaryl-heteroaryl-R'; wherein R' and R" are independently selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, and optionally substituted aryl; or one or both of R' and R" forms a fused heterocyclic ring with aryl to which the N is attached to; provided that Di and D 2 are not both hydrogen, and Di and D 2 are not optionally substituted thiophene
  • each of D ls D 2 , D 3 , and D 4 in formula X-a and formula X-b are each independently C 6 -io aryl or optionally substituted C 6 -io aryl.
  • the chromophore is represented by formula X-a or
  • the chromophore is represented by formula X-a or
  • X in formula VIII, formula X-a, and formula X-b is selected from the group consisting of -N(A 0 )-, -S-, and -Se-.
  • Z in formula VIII, formula IX-a, and formula IX- b is selected from the group consisting of -N(R a )-, -S-, and -Se-.
  • Ao in formula VIII, formula IX-a, formula IX-b, formula X-a, and formula X-b is selected from the group consisting of hydrogen, optionally substituted Ci_i 0 alkyl, optionally substituted aryl, optionally substituted heteroaryl, and optionally substituted alkoxyalkyl.
  • a 0 is selected from the group consisting of: hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl,
  • a 0 is hydrogen or Ci_g alkyl . In some embodiments A 0 is isobutyl. In some
  • a 0 is tert-butyl. In some embodiments, A 0 is In some
  • a 0 is
  • R a , R b , or R c , in formula VIII, formula IX-a, formula IX-b, formula X-a, and formula X-b are independently selected from the group consisting of hydrogen, optionally substituted Ci_io alkyl, optionally substituted aryl, optionally substituted heteroaryl, and optionally substituted alkoxyalkyl.
  • R a and R b , or R b and R c , or R a and R c together form an optionally substituted polycyclic ring system.
  • R a , R b , or R c , in formula VIII, formula IX-a, formula IX-b, formula X-a, and formula X-b are independently selected from the group consistin of hydrogen, methyl, ethyl, propyl, isopropyl butyl, isobutyl, tert-butyl, pentyl,
  • At least one of the L in formula VIII is selected from the group consisting of: 1 ,2-ethylene, acetylene, 1 ,4-phenylene, l,l '-biphenyl-4,4'- diyl, naphthalene-2,6-diyl, naphthalene- 1,4-diyl, 9H-fluorene-2,7-diyl, perylene-3,9-diyl, perylene-3,10-diyl, or pyrene-l,6-diyl, lH-pyrrole-2,5-diyl, furan-2,5-diyl, thiophen-2,5- diyl, thieno[3,2-£]thiophene-2,5-diyl, benzo[c]thiophene-l,3-diyl, dibenzo[£, ⁇ i]thiophene- 2,8-diyl, 9
  • the electron linker represents a conjugated electron system, which may be neutral or serve as an electron donor itself. In some embodiments, some examples are provided below, which may or may not contain additional attached substituents.
  • the neutral luminescent solar concentrator comprises at least one planar layer and at least one wavelength conversion layer, wherein the at least one planar layer and the at least one wavelength conversion layer may or may not be the same layer.
  • the wavelength conversion layer comprises a top surface configured for receipt and absorption of incident solar radiation, one or more chromophores configured to absorb and convert the photons to different wavelengths of light, an edge surface through which a first portion of converted photons can escape, and a bottom surface through which a second portion of the converted photons can escape.
  • the wavelength conversion layer comprises at least one UV absorbing organic photostable chromophore, wherein the wavelength conversion layer does not absorb photons having substantial absorption in the wavelength range between of about 400 nm to about 620 nm, such that the wavelength conversion layer is neutral in color.
  • the wavelength conversion layer comprises two or more organic photostable chromophores, wherein the mixture of the two or more organic photostable chromophores provides a flat absorption of incident photons in the visible wavelength range such that the wavelength conversion layer is neutral in color.
  • the photons, once absorbed by the chromophores, are re-emitted at a different wavelength and at least a portion are internally reflected and refracted within the neutral luminescent solar concentrator until they reach the edge surface.
  • the wavelength conversion layer comprises a mixture of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more chromophores.
  • the mixture of the chromophores in the wavelength conversion film determine the color of the film.
  • the chromophore mixture in the wavelength conversion film is chosen so that the film color is neutral.
  • a neutral colored wavelength conversion film is one that is substantially colorless (e.g. wherein substantially colorless means any color present is outside the range of detection using a photometer).
  • a neutral colored film is one that is essentially colorless (e.g. color that cannot be detected by the human eye).
  • more than one wavelength conversion layer may be present.
  • the chromophores in each wavelength conversion layer can be paired to neutralize the color of the individual wavelength conversion layers.
  • one layer may have one or more chromophores that provide a neutral wavelength conversion layer and the other layer may have one or more chromophores (that are the same or different from those in the other layer) that provide a neutral wavelength conversion layer.
  • the chromophores in separate wavelength conversion layers maybe paired to neutralize the color of the neutral luminescent solar concentrator.
  • one layer may have one or more chromophores that provide a colored emission and the other layer may have one or more chromophores that provide a colored emission, but the combination of the two layers provides a net neutral device.
  • transparency or transmission of the wavelength conversion film is determined by the film thickness and the loading concentration of the chromophore compounds. In some embodiments, thicker films are less transparent. In some embodiments, films with higher loading concentration of chromophores have lower transparency. In some embodiments, the transmission of visible wavelengths in the wavelength conversion layer is in the range of about 1% to about 100%. In some embodiments, the transmission of the wavelength conversion layer is in the range of about 20% to about 50%.
  • the transmission of the wavelength conversion layer is in the range of about 1% to about 10%, about 10% to about 20%, about 20% to about 30%, about 30% to about 40%, about 40% to about 50%, about 50% to about 60%, about 60% to about 70%, about 70% to about 80%, about 80% to about 90%, or about 90% to about 99%.
  • a neutral wavelength conversion layer is one that does not substantially affect the color of light transmitted through the wavelength conversion film but only affects the transmission level through the wavelength conversion layer (i.e. the brightness).
  • the loading concentration of each chromophore in the wavelength conversion film can be optimized so that the film is neutral in color. Too much or too little of one chromophore may cause the film to have a color. Additionally, too much loading of all chromophores will lower the transparency, while too little loading will lower the solar harvesting efficiency.
  • said wavelength conversion layer comprises a polymer matrix.
  • each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount in the range from about 0.001 wt. % to about 10.0 wt. %, by weight of the polymer matrix.
  • each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount in the range from about 0.01 wt. % to about 3.0 wt. %, by weight of the polymer matrix.
  • each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount in the range from about 0.01 wt. % to about 2.0 wt.
  • each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount in the range from about 0.01 wt. % to about 1.0 wt. %, by weight of the polymer matrix. In some embodiments, each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount in the range from about 0.01 wt. % to about 0.1 wt. %, about 0.1 wt. % to about 1.0 wt. %, about 1.0 wt. % to about 2.0 wt. %, about 2.0 wt. % to about 3.0 wt. %, about 3.0 wt.
  • each chromophore in the polymer matrix of the wavelength conversion layer is independently present in an amount of about: 0.001 wt. %, 0.01 wt. %, 0.1 wt. %, 1.0 wt. %, 2.0 wt. %, 3.0 wt. %, 4.0 wt. %, 5.0 wt. %, 10.0 wt. %, values between the aforementioned values, ranges spanning the aforementioned values, and otherwise.
  • the total amount of all chromophores loaded in the polymer matrix of the wavelength conversion layer is an amount in the range of about 0.1 wt. % to about 0.5 wt. %, by weight of the polymer matrix, that is the total concentration. In some embodiments, the total amount of all chromophores loaded in the polymer matrix of the wavelength conversion layer is an amount in the range of about 0.01 wt. % to about 20.0 wt. %, about 0.01 wt. % to about 15.0 wt. %, about 0.01 wt. % to about 10.0 wt. %, about 0.01 wt. % to about 5.0 wt. %, or about 0.01 wt.
  • the total amount of all chromophores loaded in the polymer matrix of the wavelength conversion layer is an amount in the range of about 0.01 wt. % to about 0.1 wt. %, about 0.1 wt. % to about 1.0 wt. %, about 1.0 wt. % to about 5.0 wt. %, about 5.0 wt. % to about 10.0 wt. %, or about 10.0 wt. % to about 20.0 wt. %, by weight of the polymer matrix.
  • the total concentration of all the chromophores in the polymer matrix of the wavelength conversion layer an amount of about: 0.001 wt. %, 0.01 wt. %, 0.1 wt. %, 1.0 wt. %, 2.0 wt. %, 3.0 wt. %, 4.0 wt. %, 5.0 wt. %, 10.0 wt. %, 15.0 wt. %, 20.0 wt. %, values between the aforementioned values, ranges spanning the aforementioned values, and otherwise.
  • the overall thickness of the at least one wavelength conversion layer may also vary over a wide range.
  • the thickness of the wavelength conversion film may affect the transparency of the solar concentrator. In some embodiments, thin films are more transparent, while thicker films are less transparent. Additionally, in some embodiments, a thicker film may also provide a higher solar harvesting efficiency.
  • the wavelength conversion layer thickness is in the range of about 0.1 ⁇ to about 1 mm. In some embodiments, the wavelength conversion layer thickness is in the range of about 0.5 ⁇ to about 0.8 mm.
  • the thickness of the wavelength conversion layer is in the range from about 0.1 ⁇ to about 5 ⁇ , about 5 ⁇ to about 10 ⁇ , about 10 ⁇ to about 100 ⁇ , or from about 100 ⁇ to about 1 mm. In some embodiments, the thickness of the wavelength conversion layer is about: 0.1 ⁇ , 5 ⁇ , 10 ⁇ , 100 ⁇ , 200 ⁇ , 300 ⁇ , 400 ⁇ , 500 ⁇ , 1 mm, values between the aforementioned values, ranges spanning the aforementioned values, and otherwise.
  • the shape of the neutral luminescent solar concentrator device helps to concentrate the solar energy towards the edges.
  • the incoming photon which may be incident on the device in a variety of angles, once absorbed by the chromophore compounds in the wavelength conversion layer, is more likely to be re-emitted in a direction that will internally reflect within the device than it is to be re-emitted in a direction that will cause it to exit the device, which is due to the thin planar geometry of the device, as is well known by a person of ordinary skill in the art.
  • photons do not necessarily need to be absorbed and re-emitted by the chromophore compounds in order to be internally reflected and refracted with the neutral luminescent solar concentrator device.
  • the incident photons into the neutral luminescent solar concentrator may be internally reflected and refracted within the device without necessarily being absorbed by the chromophore and re-emitted.
  • Different types of solar cells often utilize different wavelengths of photons differently. For example, some Silicon based devices are more efficient at converting higher wavelength photons into electricity, while CdTe based solar cells may be more efficient at converting photons in the orange and red spectrum into electricity.
  • the chromophores utilized in the wavelength conversion layer of the neutral luminescent solar concentrator can be selected such that their emission corresponds to the optimal wavelength for the solar cell that is to be attached to the device.
  • the neutral luminescent solar concentrator can be constructed to be compatible with all different types and sizes of solar cells and solar panels, including Silicon based devices, III-V and II- VI PN junction devices, CIGS thin film devices, organic sensitizer devices, organic thin film devices, CdS/CdTe thin film devices, dye sensitized devices, etc.
  • Devices such as an amorphous Silicon solar cell, a microcrystalline Silicon solar cell, and a crystalline Silicon solar cell, can also be utilized.
  • the wavelength conversion layer or layers may be sandwiched in between plates.
  • the plates are composed of glass, polymer, composite structures, crystal, or the like.
  • the plates are configured to internally reflect and refract photons towards the edge surface.
  • the plates are transparent.
  • the plates are composed of any material that is transparent.
  • the polymer matrix of the wavelength conversion layer is formed from a substance selected from the group consisting of polyethylene terephthalate, polymethyl methacrylate, polyvinyl butyral, ethylene vinyl acetate, ethylene tetrafluoroethylene, polyimide, amorphous polycarbonate, polystyrene, siloxane sol-gel, polyurethane, polyacrylate, and combinations thereof.
  • the wavelength conversion layer comprises an optically transparent polymer matrix.
  • the polymer matrix of the wavelength conversion layer may be made of one host polymer, a copolymer, or a composite of two or more polymers. In some embodiments the polymer matrix comprises 1, 2, 3, 4, 5, or more polymers.
  • the polymer matrix material used in the wavelength conversion layer has a refractive index in the range of about 1.4 to about 1.7. In some embodiments, the refractive index of the polymer matrix material used in the wavelength conversion layer is in the range of about 1.450 to about 1.550.
  • the wavelength conversion layer comprises an optically transparent polymer matrix.
  • the wavelength conversion layer can be fabricated by (i) preparing a polymer solution with dissolved polymer powder in a solvent, such as cyclopentanone, dioxane, tetrachloroethylene (TCE), etc., at a predetermined ratio; (ii) preparing a chromophore containing a polymer mixture by mixing the polymer solution with the one or more chromophores at a predetermined weight ratio to obtain a chromophore-containing polymer solution, (iii) forming the chromophore/polymer thin film by directly casting the chromophore-containing polymer solution onto a glass substrate, then heat treating the substrate from room temperature up to 100°C in 2 hours, completely removing the remaining solvent by further vacuum heating at 130°C overnight, and (iv) peeling off the chromophore/polymer thin film under the water and then drying out
  • a solvent such as cyclopen
  • Chromophores can be up-converting or down-converting.
  • at least one of the chromophores in the at least one wavelength conversion layer may be an up-conversion chromophore, meaning a chromophore that converts photons from lower energy (long wavelengths) to higher energy (short wavelengths).
  • Up-conversion dyes may include rare earth materials which have been found to absorb photons of wavelengths in the infrared (IR) region, ⁇ 975nm, and re-emit in the visible region (400- 700nm), for example, Yb , Tm , Er , Ho , and NaYF . Additional up-conversion materials are described in U.S. Patent Nos.
  • At least one of the chromophores is a down-shifting chromophore, meaning chromophores that convert photons of high energy (short wavelengths) into lower energy (long wavelengths).
  • the down-shifting chromophore may independently be a derivative of perylene, benzotriazole, benzothiadiazole, or combinations thereof, as are described above, and in U.S. Provisional Patent Application Nos.
  • the wavelength conversion layer comprises both an up-conversion chromophore and at least one down-shifting chromophore.
  • the wavelength conversion layer of the neutral luminescent solar concentrator further comprises one or multiple sensitizers.
  • the sensitizer comprises nanoparticles, nanometals, nanowires, or carbon nanotubes.
  • the sensitizer comprises a fullerene.
  • the fullerene is selected from the group consisting of optionally substituted C 6 o, optionally substituted C70, optionally substituted Cg 4 , optionally substituted single-wall carbon nanotube, and optionally substituted multi-wall carbon nanotube.
  • the fullerene is selected from the group consisting of [6,6]-phenyl-C 6 r butyricacid-methylester, [6,6]-phenyl-C7i-butyricacid-methylester, and [6,6]-phenyl-Cg5- butyricacid-methylester.
  • the sensitizer is selected from the group consisting of optionally substituted phthalocyanine, optionally substituted perylene, optionally substituted porphyrin, and optionally substituted terrylene.
  • the wavelength conversion layer further comprises a combination of sensitizers, wherein the combination of sensitizers is selected from the group consisting of optionally substituted fullerenes, optionally substituted phthalocyanines, optionally substituted perylenes, optionally substituted porphyrins, and optionally substituted terrylenes.
  • the at least one wavelength conversion layer comprises the sensitizer in an amount in the range of about 0.01% to about 5%, by weight based on the total weight of the composition.
  • the sensitizer is present in a concentration of about: 0.01 wt. %, 0.05 wt. %, 0.1 wt. %,0.5 wt. %, 1 wt. %, 2 wt. %, 5 wt. %, values between the aforementioned values, ranges spanning the aforementioned values, and otherwise.
  • the at least one wavelength conversion layer further comprises one or multiple plasticizers.
  • the plasticizer is selected from the group consisting of N-alkyl carbazole derivatives and triphenylamine derivatives.
  • the composition of the at least one wavelength conversion layer further comprises an antioxidant which may act to prevent additional degradation of the chromophore compounds.
  • the solar concentrator comprises a solar energy conversion module for the conversion of solar light energy into electricity.
  • the solar energy conversion module comprises at least one solar energy conversion device and the neutral luminescent solar concentrator, as disclosed herein, wherein the at least one solar energy conversion device is mounted to the edge surface of the neutral luminescent solar concentrator such that it receives the concentrated solar energy and converts that energy into electricity.
  • the solar energy conversion device is a photovoltaic device or solar cell.
  • additional materials may be used in the solar energy conversion module, such as glass plates, polymer layers, or reflective mirror layers.
  • the materials may be used to encapsulate the wavelength conversion layer or layers, or they may be used to protect or encapsulate both the solar cell and wavelength conversion layer(s).
  • glass plates selected from low iron glass, borosilicate glass, or soda-lime glass, may be used in the module.
  • the composition of the glass plate or polymer layers may also further comprise a strong UV absorber to block harmful high energy radiation into the solar cell. The UV absorber in the glass plates or polymer layers may also block harmful high energy radiation from the wavelength conversion layer, thus improving the lifetime of the wavelength conversion layer.
  • additional materials or layers may be used such as edge sealing tape, frame materials, polymer materials, or adhesive layers to adhere additional layers to the system.
  • the module further comprises an additional polymer layer containing a UV absorber.
  • multiple types of solar energy conversion devices may be used within the module and may be independently selected and mounted to the edge surface of the neutral luminescent solar concentrator according to the emission wavelength of the wavelength conversion layer, to provide the highest possible photoelectric conversion efficiency.
  • the mixture of chromophores in the wavelength conversion layer may be selected such that the emission spectrum of the wavelength conversion layer is optimized for a particular solar energy conversion device.
  • the solar energy conversion module further comprises a refractive index matching liquid that is used to attach the neutral luminescent solar concentrator to the light incident surface of the solar energy conversion device.
  • the refractive index matching liquid used selected from the group consisting of Series A mineral oil comprising aliphatic and alicyclic hydrocarbons, and hydrogenated terphenyl from Cargille-Sacher Labratories, Inc.
  • the module further comprises an adhesive layer.
  • an adhesive layer adheres the wavelength conversion film to the light incident surface of the solar cell.
  • the adhesive layer comprises a substance selected from the group consisting of rubber, acrylic, silicone, vinyl alkyl ether, polyester, polyamide, urethane, fluorine, epoxy, ethylene vinyl acetate, and combinations thereof.
  • the adhesive can be permanent or non-permanent.
  • the thickness of the adhesive layer is between about 1 ⁇ and 100 ⁇ .
  • the refractive index of the adhesive layer is in the range of about 1.400 to about 1.700.
  • the neutral luminescent solar concentrator may additionally have at least one microstructured layer, which is designed to further enhance the solar harvesting efficiency of solar modules by decreasing the loss of photons to the environment (see U.S. Provisional Patent Application No. 61/555,799, which is hereby incorporated by reference).
  • a layer with various microstructures on the surface i.e. pyramids or cones may increase internal reflection and refraction of the photons into the photoelectric conversion layer of the solar cell, further enhancing the solar harvesting efficiency of the device.
  • the wavelength conversion layer of the neutral luminescent solar concentrator comprising at least one planar layer and at least one wavelength conversion layer, wherein the wavelength conversion layer comprises at least one chromophore and an optically transparent polymer matrix
  • the wavelength conversion layer comprises at least one chromophore and an optically transparent polymer matrix
  • the neutral luminescent solar concentrator 101 comprises a single planar layer 110 that is a wavelength conversion layer 110.
  • incident photons 120 of various wavelengths enter the wavelength conversion layer 110.
  • the wavelength conversion layer 110 comprises a chromophore 130.
  • the photons 120 may be absorbed by one of the chromophores 130, after which the photons are re-emitted from the chromophore compounds at a different wavelength 122 as converted photons that are internally reflected 124 and refracted 126 until they reach the edge 140 where a solar cell 150 can be mounted.
  • the chromophore is a UV absorbing chromophore compound 130.
  • the UV photons 120 may be absorbed by one of the UV absorbing chromophore compounds 130, after which the photons are re-emitted from the chromophore compounds at a different wavelength 122 and are internally reflected 124 and refracted 126 until they reach the edge 140 where a solar cell 150 can be mounted.
  • the absorbed photons 122 reach the solar energy conversion device 150 via the edge 140 of the neutral luminescent concentrator 101, they are absorbed by the photoelectric conversion layer of the solar cell 150 and converted into electricity.
  • the neutral luminescent solar concentrator 201 comprises a planar layer 210 that is a wavelength conversion layer 210.
  • incident photons 120 of various wavelengths enter the wavelength conversion layer 210.
  • the wavelength conversion layer 210 comprises two or more different chromophore compounds 131, 132, 133.
  • the photons 120 may be absorbed by one of the chromophore compounds 131, after which the photons are re-emitted from the chromophore compounds at a different wavelength 122 as converted photons which are internally reflected 124 and refracted 126 until they reach the edge 140 where a solar cell 150 can be mounted.
  • the absorbed photons 122 reach the solar energy conversion device 150 via the edge 140 of the neutral luminescent concentrator 201, they are absorbed by the photoelectric conversion layer of the solar cell 150 and converted into electricity.
  • FIG. 5 illustrates another embodiment 300 of a solar energy conversion device comprising a neutral luminescent solar concentrator 301, wherein the neutral luminescent solar concentrator 301 comprises a plurality of planar layers 210, 160, 161 which include two glass or polymer layers 160 sandwiching a wavelength conversion layer 210, and mounted to a solar cell 150, wherein incident photons 120 of various wavelengths enter the neutral luminescent solar concentrator by first passing through a first glass or polymer layer 162, then entering into a wavelength conversion layer 210, wherein within the wavelength conversion layer 210, the multiple chromophore compounds 131, 132, 133 absorb photons 122 of a first wavelength and re-emit them at a second, different wavelength, and they are internally reflected 124 and refracted 126 until they reach the edge 140 of the neutral solar concentrator 140 where a solar cell 150 may be mounted. Once the absorbed photons 122 reach the solar energy conversion device 150 via the edge 140 of the neutral concentrator 301, they are absorbed
  • the neutral luminescent solar concentrator comprises a solar energy conversion device.
  • the solar energy conversion device comprises a solar cell or a photovoltaic device.
  • the neutral luminescent solar concentrator can be used to improve the efficiency of the below solar energy conversion devices.
  • Devices such as a Silicon based device, a III-V or II-VI PN junction device, a Copper-Indium-Gallium-Selenium (CIGS) thin film device, an organic sensitizer device, an organic thin film device, or a Cadmium Sulfide/Cadmium Telluride (CdS/CdTe) thin film device, can be improved.
  • the module comprises at least one photovoltaic device or solar cell comprising a Cadmium Sulfide/Cadmium Telluride solar cell.
  • the photovoltaic device or solar cell comprises a Copper Indium Gallium Diselenide solar cell.
  • the photovoltaic or solar cell comprises a III-V or II-VI PN junction device.
  • the photovoltaic or solar cell comprises an organic sensitizer device.
  • the photovoltaic or solar cell comprises an organic thin film device.
  • the photovoltaic device or solar cell comprises an amorphous Silicon (a-Si) solar cell.
  • the photovoltaic device or solar cell comprises a microcrystalline Silicon ( ⁇ -8 ⁇ ) solar cell.
  • the photovoltaic device or solar cell comprises a crystalline Silicon (c-Si) solar cell.
  • the maximum absorption and fluorescence wavelength were measured in the chromophore solution and/or in a polymer film.
  • DCM dichloromethane
  • the maximum absorption of the chromophore was 408 nm and the maximum fluorescence absorption was 548 nm upon 408 nm light illumination.
  • a polyvinylbutyral (PVB) film 0.3wt. % chromophore
  • the maximum absorption of the chromophore was 416 nm and the maximum fluorescence absorption was 515 nm upon 416 nm light illumination.
  • the wavelength differences between maximum absorption and maximum fluorescence are useful for optimizing the neutral luminescent solar concentrator device for the particular solar cell.
  • Step 1 Synthesis of 2-(4-Nitrophenyl)-2H-benzo[dl[l,2,31triazole.
  • the extract was washed with water (200 mL), concentrated to a volume of 100 mL and diluted with dichloromethane (200 mL) and methanol (200 mL).
  • the obtained solution was hydrogenated for 20 minutes at 50 psi over 10% Pd/C (2 g), filtered through a layer of Celite, and the solvent was removed under reduced pressure.
  • TFMSA trifluoromethanesulfonic acid
  • Step 1 A mixture of Intermediate E (3.84g, 10 mmol), Intermediate F (10.7g, 20 mmol), and Bis(triphenylphosphine)palladium(II) chloride (1.40g, 2.0mmol) in tetrahydrofuran was stirred and heated under argon at 70°C for 5 hours. The solvent was removed and MeOH was added (lOOmL) to the residue. The purple solid was separated by filtration, washed with MeOH, and dried to give 4,4'-(5,6-dinitrobenzo[c][l,2,5]thiadiazole- 4,7-diyl)bis(N,N-diphenylaniline) (7.0g) as purple solid.
  • Step 2 A mixture of the above crude product (calculated for 10 mmol) with iron dust (5.6g, lOOmmol) was heated in glacial acetic acid (lOOmL) at 110°C for 2 hours. The solution was poured into ice-water (200mL) and the resulting solid was separated by filtration, washed with water and dried. After washing through 2 layers of silica gel (to remove particles of iron) using ethyl DCM/hexane (3:2) gave Intermediate G (4,7-bis(4-(diphenylamino)phenyl)benzo[c][l,2,5]thiadiazole-5,6-diamine) as a light brown solid (4.50 g, 68%, after 2 steps).
  • Step 1 A mixture of benzotriazole (11.91 g, 100 mmol), l-iodo-2- methylpropane (13.8 mL, 120 mmol), potassium carbonate (41.46 g, 300 mmol), and dimethylformamide (200 mL) was stirred and heated under argon at 40°C for 2 days. The reaction mixture was poured into ice/water (1 L) and extracted with toluene/hexanes (2: 1, 2 x 500 mL). The extract was washed with 1 N HC1 (2 x 200 mL) followed by brine (100 mL), dried over anhydrous MgSC ⁇ , and the solvent was removed under reduced pressure.
  • Step 2 A mixture of 2-isobutyl-2H-benzo[ ][l,2,3]triazole (8.80 g, 50 mmol), bromine (7.7 mL, 150 mmol) and 48% HBr (50 mL) was heated at 130°C for 24 hours under a reflux condenser connected with an HBr trap. The reaction mixture was poured into ice/water (200 mL), treated with 5 N NaOH (100 mL) and extracted with dichloromethane (2 x 200 mL). The extract was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure.
  • Step 3 4,7-dibromo-2-isobutyl-2H-benzo[ ][l,2,3]triazole (17.8g, 53 mmol) was added at 0-5°C to a premixed fuming ⁇ 0 3 (7.0mL) and TFMSA (HOg) portion wise and after approximately 10 minutes the reaction mixture was placed in an oil bath and heated at 55°C for 8 hours. The solution was then cooled by pouring into 500mL of ice/water.
  • Step 1 In a three necked reaction flask equipped with argon inlet and magnetic stirring bar, was placed THF (lOOmL), Intermediate E (31.1g, 30 mmol), and argon was bubbled through for approximately 10 minutes before bis(triphenylphosphine)palladium(II) chloride (10% molar per Intermediate E, 1.80 g, 2.5 mmol) was added. The reaction was stirred under argon for 10 minutes before Intermediate F (10.6 g, 25 mmol) was added in one portion. The reaction mixture was refluxed for 22 hours. The reaction was monitored by LCMS and TLC. The reaction was cooled and MeOH (200 mL) was added while stirring.
  • Step 2 A mixture of 4,4'-(2-isobutyl-5,6-dinitro-2H- benzo[d][l,2,3]triazole-4,7-diyl)bis(N,N-diphenylaniline) (6.0 g, 8.0mmol) and iron powder (4.5 g, 80 mmol) was heated and stirred in glacial acetic acid (100 mL) at 130°C for 2 hours. The reaction was monitored by LCMS and TLC.
  • Step 1 Intermediate I (5.54g, 8 mmol) was dissolved in 150 mL of acetic acid and cooled in an ice/water bath before 12 mL of 1M solution of NaN0 2 in water was added. After 10 minutes the reaction was complete. Diluting with 400 mL of water afforded an orange color solid which was separated by filtration, washed and dried to give 4,4'-(6-isobutyl-l,6-dihydrobenzo[l,2-d:4,5-d * ]bis([l,2,3]triazole)-4,8-diyl)bis(N,N- diphenylaniline) as an orange solid (2.72g, 48%).
  • Step 2 Then, 1.70 g of 4,4'-(6-isobutyl-l,6-dihydrobenzo[l,2-d:4,5- d']bis([l,2,3]triazole)-4,8-diyl)bis(N,N-diphenylaniline, calculated for 2.5 mmol was dissolved in DMF (30 mL). Potassium carbonate (2.80 g, 20 mmol) was added, followed by 2-butoxyethyl 4-methylbenzenesulfonate (1.36 g, 5 mmol) and the reaction mixture was heated at 125°C for 50 minutes. The solution was rotavaped and the residue was triturated with MeOH.
  • Step 1 Intermediate G (6.5 g, 10 mmol) was dissolved in a mixture of THF and acetic acid (25 mL + 25mL) in a beaker and vigorously stirred in ice/water bath to keep the temperature below 10°C.
  • the solution of NaN0 2 (0.83 g) in 10 mL of water was prepared and after cooling in the same bath was added portion wise to the reaction mixture. After 10 minutes, the mixture was removed from the cooling bath and left to stir at room temperature for one hour (monitored by TLC, Hexane/EA-4: 1). A strong purple color of the product formed in comparison to yellow color of the starting material.
  • Step 2 The above crude material (3.32 g, 5 mmol) was dissolved in 20 mL of DMF. 2-ethylhexyl 4-methylbenzenesulfonate (1.71 g, 7.0 mmol) was added followed by K 2 CO 3 (1.38 g, 10 mmol). The reaction mixture was stirred at 80°C (oil bath) for 4 hours. The reaction was monitored by TLC, and a strong blue color was observed. After reaction was accomplished it was poured into water and the resulting precipitate was separated, washed with water, followed by MeOH, and dried in a vacuum oven.
  • a wavelength conversion film 1 10, which comprises at least one UV absorbing chromophore, and a polymer matrix is fabricated by (i) preparing a 20 wt. % Polyvinyl butyral (PVB60T) (from Aldrich and used as received) polymer solution with dissolved polymer powder in cyclopentanone; (ii) preparing a chromophore containing a PVB60T matrix by mixing the PVB60T polymer solution with the synthesized Compound 1 (green chromophore with absorption peak at 450 nm in PVB60T) at a weight ratio (Compound 1/PVB60T) of 0.3 wt.
  • PVB60T Polyvinyl butyral
  • the film was then laminated between two B270 type glass plates with dimensions 2 inch x 2 inch x 0.06 inch, similar to the embodiment shown in Figure 5.
  • the glass plates were approximately 2 inch x 2 inch x 0.06 inch, with the major planar surface area dimensions of 2 inches by 2 inches.
  • the remaining three edges of the luminescent solar concentrator were covered with a reflective tape to prevent photon escape and reflect the photons back towards the edge of the luminescent solar concentrator where the solar cell device is mounted.
  • the solar cell photoelectric conversion efficiency was measured by a Newport 300W full spectrum solar simulator system. The light intensity was adjusted to one sun (AM1.5G) by a 2cm x 2cm calibrated reference monocrystalline silicon solar cell. Then the I-V characterization of the c-Si solar cell was performed under the same irradiation and its efficiency is calculated by the Newport software program which is installed in the simulator.
  • One c-Si solar cell (from IXYS Corp. model KXOB22-12X1) used in this study has an efficiency
  • Example 2 is synthesized the same as Example 1, except that Compound 2 (UV chromophore with absorption peak at 388 nm in PVB) is used.
  • ce ii +L sc was measured under same one sun exposure, and determined to be 0.92%>.
  • Table 1 below shows the various device parameters and the solar cell efficiency measured for each example device.
  • the neutral luminescent solar concentrator device using UV absorbing chromophores can successfully be used to concentrate solar radiation into c-Si solar cell devices.
  • the solar photoelectric conversion efficiency of the crystalline Silicon solar cell can be varied significantly depending on the size of the LSC, the number of wavelength conversion films used in the LSC, and the chromophores utilized in the wavelength conversion films.
  • the prepared examples showed efficiencies of greater than 0.9%. Due to the high cost of Silicon solar cells, neutral luminescent solar concentrators, as described herein, may provide a significant improvement in the price per watt of electricity generated by these devices and enable the use of these devices as windows for building integrated photovoltaic applications.
  • a wavelength conversion film comprising a mixture of four organic chromophores, and an optically transparent polymer matrix, was fabricated by (i) preparing a 20 wt. % Polyvinylbutyral (PVB60T purchased from Aldrich and used as received) polymer solution with dissolved polymer powder in cyclopentanone; (ii) preparing the chromophore containing a PVB60T matrix by mixing the PVB60T polymer solution with the synthesized Compounds 3, 4, 5, and 6 at a weight ratio of Compound 3/PVB60T of 0.0701 wt. %, Compound 4/PVB60T of 0.0608 , Compound 5/PVB60T of 0.0234 wt.
  • PVB60T Polyvinylbutyral
  • the film was then laminated between two low iron glass plates to form the neutral luminescent solar concentrator, similar to the embodiment shown in Figure 5.
  • the glass plates were approximately 2 inch x 2 inch x 0.08 inch, with the major planar surface area dimensions of 2 inches by 2 inches.
  • the remaining three edges of the luminescent solar concentrator were covered with a reflective tape to prevent photon escape and reflect the photons back towards the edge of the luminescent solar concentrator where the solar cell device is mounted.
  • the Solar cell photoelectric conversion efficiency was measured by a Newport 300W full spectrum solar simulator system. The light intensity was adjusted to one sun (AM1.5G) by a 2cm x 2cm calibrated reference monocrystalline silicon solar cell. Then the I-V characterization of the c-Si solar cell was performed under the same irradiation and its efficiency is calculated by the Newport software program which is installed in the simulator. The c-Si solar cell used in this study has an efficiency r
  • Figure 2A shows the individual absorption spectrums of a PVB60T film containing only one of the chromophore Compounds 3-6.
  • Figure 2B shows the absorption spectrum of the Example 3 PVB60T film with the mixture of all four chromophore Compounds 3-6.
  • the mixture of Compounds 3-6 achieved a flat absorption, appearing colorless, from about 400 nm to about 620 nm with less than or equal to 5% variation between the minimum and maximum in the wavelength range. Additionally, the transmission of the film was measured and determined to be 20%.
  • the absorption and transmission of the wavelength conversion films were measured using a UV- Vis-NIR Spectrophotometer model UV-3600 from Shimadzu.
  • Example 4 was synthesized using the same method as given in Example 3, except that a mixture of five chromophore compounds was used.
  • the wavelength conversion film comprised a mixture of Chromophore Compounds 3-7 in a PVB60T polymer at a weight ratio of Compound 3/PVB60T of 0.0475 wt. %, Compound 4/PVB60T of 0.0411 wt. %, Compound 5/PVB60T of 0.0153 wt. %, Compound 6/PVB60T of 0.0858 wt. %, and Compound 7/PVB60T of 0.0056 wt. % (total chromophore loading in the PVB60T was 0.1953wt.
  • Figure 6 shows the absorption spectrum of the Example 4 PVB60T film with the mixture of all five chromophore Compounds 3-7. As shown in Figure 6, the mixture of Compounds 3-7 achieved a flat absorption from about 400 nm to about 660 nm, appearing colorless, with less than or equal to 2% variation between the minimum and maximum in the wavelength range.
  • Comparative Example 5 was synthesized using the same method as given in Example 3, except that only one chromophore was used in the wavelength conversion layer.
  • Compound 8 (orange chromophore with emission peak at 547 nm in PVB) was used in the wavelength conversion film at a weight ratio of Chromophore 8/PVB60T of 0.3wt. %.
  • the Comparative Example 5 film was prepared at a thickness of 0.4mm. This film was orange in color.
  • ce ii +L sc was measured under same one sun exposure, and determined to be 1.07%.
  • Comparative Example 6 was synthesized using the same method as given in Comparative Example 5, except that the film was prepared at a thickness of 0.6mm.
  • ce ii + Lsc was measured under same one sun exposure, and determined to be 1.13%.
  • Table 2 below compares the solar harvesting efficiencies of the Example 4- 6 devices.
  • Table 2 shows that the solar harvesting efficiency of the mixture of chromophores is comparable to that of single chromophore films.
  • the Example 3 mixture of chromophores provides a neutral color film which maintains 20% of light transmission. Because of the neutral color, adequate light transmission, and high solar harvesting efficiency, this neutral luminescent solar concentrator is useful for a variety of applications, including for use as window glass in buildings and cars. Due to the high cost of solar cells, neutral luminescent solar concentrators, as described herein, may provide a significant improvement in the price per watt of electricity generated by these devices. These results also illustrate that further optimization of the neutral luminescent solar concentrator devices, could potentially provide even greater efficiencies of more than 1.5%, or more than 2%, or possibly more than 5%, depending on the solar cell devices that are used.
  • the object of this current invention is to provide a neutral luminescent solar concentrator comprising at least one planar layer and at least one wavelength conversion layer, wherein the wavelength conversion layer comprises at least one chromophore compound, which is suitable for use in solar harvesting systems.
  • the use of this neutral luminescent solar concentrator applied to photovoltaic devices provides a high efficiency low cost solar harvesting system that is neutral in color and provides adequate transmission.

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  • Engineering & Computer Science (AREA)
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Abstract

L'invention concerne des concentrateurs solaires neutres luminescents comprenant au moins une couche de conversion de longueur d'onde. Selon certains modes de réalisation, ladite couche de conversion de longueur d'onde comprend un chromophore absorbant les UV. Selon des modes de réalisation, ladite couche de conversion de longueur d'onde comprend au moins deux chromophores absorbant la longueur d'onde visible. Selon certains modes de réalisation, le concentrateur solaire neutre luminescent est positionné à côté d'au moins un dispositif photovoltaïque ou cellule solaire et agit de façon à absorber des photons incidents d'une plage de longueurs d'onde particulière, et à réémettre ces photons à une longueur d'onde différente, les photons réémis étant réfléchis à l'intérieur et réfractés jusqu'à ce qu'ils atteignent le dispositif photovoltaïque ou cellule solaire où ils peuvent être absorbés et convertis en électricité.
PCT/US2014/050504 2013-08-13 2014-08-11 Concentrateur solaire luminescent utilisant des composés organiques photostables chromophores Ceased WO2015023574A1 (fr)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016204337A (ja) * 2015-04-28 2016-12-08 日東電工株式会社 ベンゾトリアゾール化合物およびそれを用いた樹脂組成物ならびに波長変換層
WO2016198496A1 (fr) * 2015-06-09 2016-12-15 Solvay Specialty Polymers Italy S.P.A. Composition comprenant un composé luminescent
CN110483426A (zh) * 2019-07-18 2019-11-22 江苏大学 一种以苯并三氮唑为核心结构的空穴传输材料的合成方法及应用
CN112020825A (zh) * 2018-04-19 2020-12-01 艾尼股份公司 中性着色的发光太阳能集中器
JP2021038336A (ja) * 2019-09-04 2021-03-11 学校法人 中村産業学園 蛍光色素
TWI768777B (zh) * 2020-03-20 2022-06-21 日商日東電工股份有限公司 含硼環狀發光化合物和含有該含硼環狀發光化合物的色轉換膜
EP4177969A1 (fr) * 2021-11-05 2023-05-10 Korea Electronics Technology Institute Concentrateur de lumière à base de point quantique, et module photovoltaïque le comprenant
WO2024082959A1 (fr) * 2022-10-19 2024-04-25 The Hong Kong University Of Science And Technology Dérivés de [1,2,3]triazolo[4,5-f]-2,1,3-benzothiadiazole fluorescents pour théranostique accélérée du cancer
CN118878555A (zh) * 2024-06-28 2024-11-01 深圳大学 一类官能团化近红外二区探针分子及其构建新方法、应用
US12477888B2 (en) 2023-03-20 2025-11-18 Andluca Technologies Inc. Supplementing the power generation of transparent solar energy harvesting devices comprising luminophores
US12490572B2 (en) 2023-03-20 2025-12-02 Andluca Technologies Inc. Supplementing the power generation of visibly transparent solar energy harvesting devices comprising organic semiconductors

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130074927A1 (en) * 2011-09-26 2013-03-28 Nitto Denko Corporation Highly-fluorescent and photo-stable chromophores for enhanced solar harvesting efficiency
US20130089946A1 (en) * 2011-10-05 2013-04-11 Nitto Denko Corporation Wavelength conversion film having pressure sensitive adhesive layer to enhance solar harvesting efficiency
WO2013067288A1 (fr) * 2011-11-04 2013-05-10 Nitto Denko Corporation Films micro-structurés à conversion de longueur d'onde pour efficacité d'accumulation d'énergie solaire améliorée
US20130139868A1 (en) * 2011-12-06 2013-06-06 Nitto Denko Corporation Wavelength conversion material as encapsulate for solar module systems to enhance solar harvesting efficiency
WO2013116559A1 (fr) * 2012-02-01 2013-08-08 Nitto Denko Corporation Type d'adhésif sensible à la pression de bande de conversion de longueur d'onde pour améliorer l'efficacité d'accumulation d'énergie solaire

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130074927A1 (en) * 2011-09-26 2013-03-28 Nitto Denko Corporation Highly-fluorescent and photo-stable chromophores for enhanced solar harvesting efficiency
US20130089946A1 (en) * 2011-10-05 2013-04-11 Nitto Denko Corporation Wavelength conversion film having pressure sensitive adhesive layer to enhance solar harvesting efficiency
WO2013067288A1 (fr) * 2011-11-04 2013-05-10 Nitto Denko Corporation Films micro-structurés à conversion de longueur d'onde pour efficacité d'accumulation d'énergie solaire améliorée
US20130139868A1 (en) * 2011-12-06 2013-06-06 Nitto Denko Corporation Wavelength conversion material as encapsulate for solar module systems to enhance solar harvesting efficiency
WO2013116559A1 (fr) * 2012-02-01 2013-08-08 Nitto Denko Corporation Type d'adhésif sensible à la pression de bande de conversion de longueur d'onde pour améliorer l'efficacité d'accumulation d'énergie solaire

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016204337A (ja) * 2015-04-28 2016-12-08 日東電工株式会社 ベンゾトリアゾール化合物およびそれを用いた樹脂組成物ならびに波長変換層
WO2016198496A1 (fr) * 2015-06-09 2016-12-15 Solvay Specialty Polymers Italy S.P.A. Composition comprenant un composé luminescent
CN112020825A (zh) * 2018-04-19 2020-12-01 艾尼股份公司 中性着色的发光太阳能集中器
US20210111360A1 (en) * 2018-04-19 2021-04-15 Eni S.P.A. Luminescent solar concentrators of neutral coloration
CN112020825B (zh) * 2018-04-19 2024-06-11 艾尼股份公司 中性着色的发光太阳能集中器
US11800728B2 (en) * 2018-04-19 2023-10-24 Eni S.P.A. Luminescent solar concentrators of neutral coloration
CN110483426A (zh) * 2019-07-18 2019-11-22 江苏大学 一种以苯并三氮唑为核心结构的空穴传输材料的合成方法及应用
JP7479660B2 (ja) 2019-09-04 2024-05-09 学校法人 中村産業学園 蛍光色素
JP2021038336A (ja) * 2019-09-04 2021-03-11 学校法人 中村産業学園 蛍光色素
TWI768777B (zh) * 2020-03-20 2022-06-21 日商日東電工股份有限公司 含硼環狀發光化合物和含有該含硼環狀發光化合物的色轉換膜
EP4177969A1 (fr) * 2021-11-05 2023-05-10 Korea Electronics Technology Institute Concentrateur de lumière à base de point quantique, et module photovoltaïque le comprenant
WO2024082959A1 (fr) * 2022-10-19 2024-04-25 The Hong Kong University Of Science And Technology Dérivés de [1,2,3]triazolo[4,5-f]-2,1,3-benzothiadiazole fluorescents pour théranostique accélérée du cancer
US12477888B2 (en) 2023-03-20 2025-11-18 Andluca Technologies Inc. Supplementing the power generation of transparent solar energy harvesting devices comprising luminophores
US12490572B2 (en) 2023-03-20 2025-12-02 Andluca Technologies Inc. Supplementing the power generation of visibly transparent solar energy harvesting devices comprising organic semiconductors
CN118878555A (zh) * 2024-06-28 2024-11-01 深圳大学 一类官能团化近红外二区探针分子及其构建新方法、应用

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